Air volume adjustment knob for a spray gun



FIG. 1 is a perspective view of an air volume adjustment knob for a spray gun showing my present design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a right view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view. 

I claim, the ornamental design for an air volume adjustment knob for a spray gun, as shown and described. 